This project is a multidisciplinary investigation of the effects of low level lead exposure on development. Epidemiologic studies of heretofore unidentified lead burden in school age children are being conducted employing lead levels in shed deciduous teeth as the primary index of exposure. The performance of children with elevated lead burdens and appropriate controls are then measured along a number of neuropsychologic dimensions. Animal models of lead exposure insufficient to yield histopathologic change are being produced and studied for evidence of effects in CNS transport, neurochemistry, and ultrastructural anatomy.